The invention relates to apparatus for, and methods of, welding a base material such as steel. The invention relates particularly to arc welding apparatus and methods that allow easy viewing of a welding point on a base material.
According to a type of arc welding method, a nonconsumable electrode is moved close to a base material, and a high voltage with a high-frequency voltage superimposed thereon is applied between the electrode and the base material. Then the electrode is moved away from the base material, and an electric arc is created between the electrode and the base material, thereby melting the base material with its heat. This type of method however requires significant operator skill because of its inherent difficulty in creating a molten weld pool at a desired welding point.
In view of the foregoing, JP H10-006006A discloses an arc welding apparatus that is adapted to indicate a welding point on a workpiece to an operator.
The prior art apparatus is provided with a slit light source for illuminating a welding point, an arc monitor for monitoring a molten weld pool, and an image synthesizer. The prior art apparatus is adapted to allow an operator to view the welding point on a display screen of the arc monitor.
However, the prior art apparatus has the following problems. The provision of the slit light source and the arc monitor causes the prior art apparatus to have a complicated, and therefore expensive, configuration. Also, the prior art apparatus necessitates an operator to look at each of the monitor and the base material alternately and repeatedly during a welding operation, resulting in poor operability.
In light of the foregoing problems, a feature of the invention is to provide an inexpensive, and operable, arc welding apparatus and method that allow a welding point on a base material to be appropriately indicated to an operator.
Another feature of the invention is to provide an arc welding apparatus and method that prevent generation of high-frequency noise during an arc welding operation.
Still another feature of the invention is to provide an arc welding apparatus and method that allow smooth arc transition during an arc welding operation.